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package jdk.javadoc.internal.doclets.toolkit.util.links;

import java.util.ArrayList;
import java.util.List;

import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.lang.model.element.TypeParameterElement;
import javax.lang.model.type.ArrayType;
import javax.lang.model.type.DeclaredType;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.type.TypeVariable;
import javax.lang.model.type.WildcardType;
import javax.lang.model.util.SimpleTypeVisitor9;

import jdk.javadoc.internal.doclets.formats.html.LinkInfoImpl;
import jdk.javadoc.internal.doclets.toolkit.Content;
import jdk.javadoc.internal.doclets.toolkit.util.Utils;

A factory that constructs links from given link information.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
Author:
Jamie Ho/**
 * A factory that constructs links from given link information.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 *
 * @author Jamie Ho
 */
public abstract class LinkFactory {

    
Return an empty instance of a content object.
Returns:
an empty instance of a content object./**
     * Return an empty instance of a content object.
     *
     * @return an empty instance of a content object.
     */
    protected abstract Content newContent();

    
Constructs a link from the given link information.
Params:
linkInfo – the information about the link.
Returns:
the output of the link./**
     * Constructs a link from the given link information.
     *
     * @param linkInfo the information about the link.
     * @return the output of the link.
     */
    public Content getLink(LinkInfo linkInfo) {
        Utils utils = ((LinkInfoImpl) linkInfo).configuration.utils;
        if (linkInfo.type != null) {
            SimpleTypeVisitor9<Content, LinkInfo> linkVisitor =
                    new SimpleTypeVisitor9<Content, LinkInfo>() {

                TypeMirror componentType = utils.getComponentType(linkInfo.type);
                Content link = newContent();

                // handles primitives, no types and error types
                @Override
                protected Content defaultAction(TypeMirror type, LinkInfo linkInfo) {
                    link.addContent(utils.getTypeName(type, false));
                    return link;
                }

                int currentDepth = 0;
                @Override
                public Content visitArray(ArrayType type, LinkInfo linkInfo) {
                    // keep track of the dimension depth and replace the last dimension
                    // specifier with vararags, when the stack is fully unwound.
                    currentDepth++;
                    linkInfo.type = type.getComponentType();
                    visit(linkInfo.type, linkInfo);
                    currentDepth--;
                    if (utils.isAnnotated(type)) {
                        linkInfo.type = type;
                        link.addContent(" ");
                        link.addContent(getTypeAnnotationLinks(linkInfo));
                    }
                    // use vararg if required
                    if (linkInfo.isVarArg && currentDepth == 0) {
                        link.addContent("...");
                    } else {
                        link.addContent("[]");
                    }
                    return link;
                }

                @Override
                public Content visitWildcard(WildcardType type, LinkInfo linkInfo) {
                    linkInfo.isTypeBound = true;
                    link.addContent("?");
                    TypeMirror extendsBound = type.getExtendsBound();
                    if (extendsBound != null) {
                        link.addContent(" extends ");
                        setBoundsLinkInfo(linkInfo, extendsBound);
                        link.addContent(getLink(linkInfo));
                    }
                    TypeMirror superBound = type.getSuperBound();
                    if (superBound != null) {
                        link.addContent(" super ");
                        setBoundsLinkInfo(linkInfo, superBound);
                        link.addContent(getLink(linkInfo));
                    }
                    return link;
                }

                @Override
                public Content visitTypeVariable(TypeVariable type, LinkInfo linkInfo) {
                    link.addContent(getTypeAnnotationLinks(linkInfo));
                    linkInfo.isTypeBound = true;
                    TypeVariable typevariable = (utils.isArrayType(type))
                            ? (TypeVariable) componentType
                            : type;
                    Element owner = typevariable.asElement().getEnclosingElement();
                    if ((!linkInfo.excludeTypeParameterLinks) && utils.isTypeElement(owner)) {
                        linkInfo.typeElement = (TypeElement) owner;
                        Content label = newContent();
                        label.addContent(utils.getTypeName(type, false));
                        linkInfo.label = label;
                        link.addContent(getClassLink(linkInfo));
                    } else {
                        // No need to link method type parameters.
                        link.addContent(utils.getTypeName(typevariable, false));
                    }

                    if (!linkInfo.excludeTypeBounds) {
                        linkInfo.excludeTypeBounds = true;
                        TypeParameterElement tpe = ((TypeParameterElement) typevariable.asElement());
                        boolean more = false;
                        List<? extends TypeMirror> bounds = utils.getBounds(tpe);
                        for (TypeMirror bound : bounds) {
                            // we get everything as extends java.lang.Object we suppress
                            // all of them except those that have multiple extends
                            if (bounds.size() == 1 &&
                                    bound.equals(utils.getObjectType()) &&
                                    !utils.isAnnotated(bound)) {
                                continue;
                            }
                            link.addContent(more ? " & " : " extends ");
                            setBoundsLinkInfo(linkInfo, bound);
                            link.addContent(getLink(linkInfo));
                            more = true;
                        }
                    }
                    return link;
                }

                @Override
                public Content visitDeclared(DeclaredType type, LinkInfo linkInfo) {
                    if (linkInfo.isTypeBound && linkInfo.excludeTypeBoundsLinks) {
                        // Since we are excluding type parameter links, we should not
                        // be linking to the type bound.
                        link.addContent(utils.getTypeName(type, false));
                        link.addContent(getTypeParameterLinks(linkInfo));
                        return link;
                    } else {
                        link = newContent();
                        link.addContent(getTypeAnnotationLinks(linkInfo));
                        linkInfo.typeElement = utils.asTypeElement(type);
                        link.addContent(getClassLink(linkInfo));
                        if (linkInfo.includeTypeAsSepLink) {
                            link.addContent(getTypeParameterLinks(linkInfo, false));
                        }
                    }
                    return link;
                }
            };
            return linkVisitor.visit(linkInfo.type, linkInfo);
        } else if (linkInfo.typeElement != null) {
            Content link = newContent();
            link.addContent(getClassLink(linkInfo));
            if (linkInfo.includeTypeAsSepLink) {
                link.addContent(getTypeParameterLinks(linkInfo, false));
            }
            return link;
        } else {
            return null;
        }
    }

    private void setBoundsLinkInfo(LinkInfo linkInfo, TypeMirror bound) {
        linkInfo.typeElement = null;
        linkInfo.label = null;
        linkInfo.type = bound;
    }

    
Return the link to the given class.
Params:
linkInfo – the information about the link to construct.
Returns:
the link for the given class./**
     * Return the link to the given class.
     *
     * @param linkInfo the information about the link to construct.
     *
     * @return the link for the given class.
     */
    protected abstract Content getClassLink(LinkInfo linkInfo);

    
Return the link to the given type parameter.
Params:
linkInfo –     the information about the link to construct.
typeParam – the type parameter to link to./**
     * Return the link to the given type parameter.
     *
     * @param linkInfo     the information about the link to construct.
     * @param typeParam the type parameter to link to.
     */
    protected abstract Content getTypeParameterLink(LinkInfo linkInfo, TypeMirror typeParam);

    protected abstract Content getTypeAnnotationLink(LinkInfo linkInfo, AnnotationMirror annotation);

    
Return the links to the type parameters.
Params:
linkInfo –     the information about the link to construct.
Returns:
the links to the type parameters./**
     * Return the links to the type parameters.
     *
     * @param linkInfo     the information about the link to construct.
     * @return the links to the type parameters.
     */
    public Content getTypeParameterLinks(LinkInfo linkInfo) {
        return getTypeParameterLinks(linkInfo, true);
    }

    
Return the links to the type parameters.
Params:
linkInfo –     the information about the link to construct.
isClassLabel – true if this is a class label.  False if it is
                    the type parameters portion of the link.
Returns:
the links to the type parameters./**
     * Return the links to the type parameters.
     *
     * @param linkInfo     the information about the link to construct.
     * @param isClassLabel true if this is a class label.  False if it is
     *                     the type parameters portion of the link.
     * @return the links to the type parameters.
     */
    public Content getTypeParameterLinks(LinkInfo linkInfo, boolean isClassLabel) {
        Utils utils = ((LinkInfoImpl)linkInfo).utils;
        Content links = newContent();
        List<TypeMirror> vars = new ArrayList<>();
        TypeMirror ctype = linkInfo.type != null
                ? utils.getComponentType(linkInfo.type)
                : null;
        if (linkInfo.executableElement != null) {
            linkInfo.executableElement.getTypeParameters().stream().forEach((t) -> {
                vars.add(t.asType());
            });
        } else if (linkInfo.type != null && utils.isDeclaredType(linkInfo.type)) {
            ((DeclaredType)linkInfo.type).getTypeArguments().stream().forEach(vars::add);
        } else if (ctype != null && utils.isDeclaredType(ctype)) {
            ((DeclaredType)ctype).getTypeArguments().stream().forEach(vars::add);
        } else if (linkInfo.typeElement != null) {
            linkInfo.typeElement.getTypeParameters().stream().forEach((t) -> {
                vars.add(t.asType());
            });
        } else {
            // Nothing to document.
            return links;
        }
        if (((linkInfo.includeTypeInClassLinkLabel && isClassLabel)
                || (linkInfo.includeTypeAsSepLink && !isClassLabel)) && !vars.isEmpty()) {
            links.addContent("<");
            boolean many = false;
            for (TypeMirror t : vars) {
                if (many) {
                    links.addContent(",");
                }
                links.addContent(getTypeParameterLink(linkInfo, t));
                many = true;
            }
            links.addContent(">");
        }
        return links;
    }

    public Content getTypeAnnotationLinks(LinkInfo linkInfo) {
        Utils utils = ((LinkInfoImpl)linkInfo).utils;
        Content links = newContent();
        if (!utils.isAnnotated(linkInfo.type))
            return links;

        List<? extends AnnotationMirror> annotations = linkInfo.type.getAnnotationMirrors();
        boolean needSpace = false;
        for (AnnotationMirror anno : annotations) {
            if (needSpace) {
                links.addContent(" ");
            }
            links.addContent(getTypeAnnotationLink(linkInfo, anno));
            needSpace = true;
        }

        links.addContent(" ");
        return links;
    }
}